source of renewable energy. One of the principal reasons for the preferred use of
husk is its easy procurement, i.e., it is available at the rice mills. In the case of rice
straw, however, its collection is a tedious task and its availability is limited to
harvest time. The logistics of collection could be improved through baling but the
necessary equipment is expensive and its purchase is uneconomical for most rice
farmers. Thus, technologies that enable straw to be used for energy generation must
be efficient to compensate for the high costs involved in straw collection.
3 Agricultural Residues for Power Generation
Punjab produces around 23 million tons of rice straw and 17 million tons of wheat
straw annually (Agrawal et al. 2006). More than 80 % of paddy straw (18.4 million tons) and almost 50 % wheat straw (8.5 million tons) produced in the state are
burnt in fields annually. Almost all of paddy straw, except Basmati paddy, is burnt
in the field to enable early sowing of next crop. Recently, the farmers have extended
this practice to wheat crop also. Although part of the wheat straw is used as dry
fodder for cattle, the remaining straw is usually burnt for quick disposal.
Biomass, such as agricultural residue, bagasse, cotton stalks, rice husk, etc., is
emerging as a viable source of power. Direct burning of such waste is inefficient
and leads to pollution. When combusted in a gasifier at low oxygen and high
temperature, biomass can be converted into a gaseous fuel known as producer gas.
This gas has a lower calorific value compared to natural gas or liquefied petroleum
gas, but can be burnt with high efficiency and without emitting smoke.
The advantages of utilizing crop residue over and above conventional resources
are that the residue is renewable, readily available, and can be used successfully by
burning in boilers with an efficiency of 99 %. Further, they are available at low cost
relative to coal and their ash contents are also much less (as compared to 36 % ash
content of coal).
The calorific values of both coal and paddy straw are comparable, i.e., 4200 and
3590 kcal/kg, respectively. Additional income to the farmers from the sale of straw
is an added advantage. At the same time, state agencies involved could also take
advantage of carbon credit policy setup under the UNFCCC (United Nation
Framework Convention on Climate Change). The policy involves the allocation of
credits to programs which help in curbing global warming. The Indian government
should encourage private parties/agencies to take advantage of this carbon credit
policy of UNFCCC.
Biomass-based power plants of 10–20 MW capacity setup in a group of villages
or every Taluka can meet energy needs of villagers and employ thousands of
people. Kirangatevalu village in Karnataka is a prime example in this regard. The
initial electrification of Kirangatevalu meant supply of power to a few homes and
farms for 4–5 h a day. The transformation of the village is the result of an initiative
taken by a private firm that has set up a power plant using agricultural waste such as
sugarcane refuse and coconut fronds that are plentiful in the area. Villagers sell their
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P. Kumar
husk is its easy procurement, i.e., it is available at the rice mills. In the case of rice
straw, however, its collection is a tedious task and its availability is limited to
harvest time. The logistics of collection could be improved through baling but the
necessary equipment is expensive and its purchase is uneconomical for most rice
farmers. Thus, technologies that enable straw to be used for energy generation must
be efficient to compensate for the high costs involved in straw collection.
3 Agricultural Residues for Power Generation
Punjab produces around 23 million tons of rice straw and 17 million tons of wheat
straw annually (Agrawal et al. 2006). More than 80 % of paddy straw (18.4 million tons) and almost 50 % wheat straw (8.5 million tons) produced in the state are
burnt in fields annually. Almost all of paddy straw, except Basmati paddy, is burnt
in the field to enable early sowing of next crop. Recently, the farmers have extended
this practice to wheat crop also. Although part of the wheat straw is used as dry
fodder for cattle, the remaining straw is usually burnt for quick disposal.
Biomass, such as agricultural residue, bagasse, cotton stalks, rice husk, etc., is
emerging as a viable source of power. Direct burning of such waste is inefficient
and leads to pollution. When combusted in a gasifier at low oxygen and high
temperature, biomass can be converted into a gaseous fuel known as producer gas.
This gas has a lower calorific value compared to natural gas or liquefied petroleum
gas, but can be burnt with high efficiency and without emitting smoke.
The advantages of utilizing crop residue over and above conventional resources
are that the residue is renewable, readily available, and can be used successfully by
burning in boilers with an efficiency of 99 %. Further, they are available at low cost
relative to coal and their ash contents are also much less (as compared to 36 % ash
content of coal).
The calorific values of both coal and paddy straw are comparable, i.e., 4200 and
3590 kcal/kg, respectively. Additional income to the farmers from the sale of straw
is an added advantage. At the same time, state agencies involved could also take
advantage of carbon credit policy setup under the UNFCCC (United Nation
Framework Convention on Climate Change). The policy involves the allocation of
credits to programs which help in curbing global warming. The Indian government
should encourage private parties/agencies to take advantage of this carbon credit
policy of UNFCCC.
Biomass-based power plants of 10–20 MW capacity setup in a group of villages
or every Taluka can meet energy needs of villagers and employ thousands of
people. Kirangatevalu village in Karnataka is a prime example in this regard. The
initial electrification of Kirangatevalu meant supply of power to a few homes and
farms for 4–5 h a day. The transformation of the village is the result of an initiative
taken by a private firm that has set up a power plant using agricultural waste such as
sugarcane refuse and coconut fronds that are plentiful in the area. Villagers sell their
512
P. Kumar